This invention relates to a 6-(1-fluoroalkyl)-4-pyrimidone and processes for producing the same, more specifically, to a novel 6-(1-fluoroalkyl)-4-pyrimidone which is important as a synthetic intermediate of aminopyrimidine derivatives which are useful as acaricides, fungicides and nematocides, and processes for producing the same.
Aminopyrimidine derivatives useful as insecticides, acaricides, fungicides or nematocides have been described, for example, in Japanese Provisional Patent Publications No. 230036/1993, No. 25187/1994, No. 116247/1994, No. 247939/1994, No. 258223/1995, etc. However, the synthetic intermediates of the present invention have not yet been known as synthetic intermediates for the aminopyrimidine derivatives, and thus, the process for producing the same has not yet been known.
The present invention provides a novel 6-(1-fluoroalkyl)-4-pyrimidone which is important as a synthetic intermediate and a process for producing the same.
The present invention solves the above-mentioned problems, and as a result, 6-(1-fluoroalkyl)-4-pyrimidone which is a novel compound can be an important intermediate of the above-mentioned useful aminopyrimidine derivatives. A process for producing 6-(1-fluoroalkyl)-4-pyrimidone is also set forth.
The first aspect of the present invention relates to 6-(1-fluoroalkyl)-4-pyrimidones represented by the following formula (1): 
wherein R1 represents an alkyl group; R2 represents a hydrogen atom or an alkyl group; and R3 represents a hydrogen atom, an alkyl group or a chlorine atom.
The second aspect of the invention relates to a process for producing 6-(1-fluoroalkyl)-4-pyrimidones represented by the following formula (1-A): 
wherein R1 and R2 have the same meanings as defined above; and R3xe2x80x2 represents a hydrogen atom or an alkyl group,
which comprises allowing a 4-fluoro-3-oxocarboxylate represented by the following formula (2): 
wherein R1, R2 and R3xe2x80x2 have the same meanings as defined above; and
R4 represents an alkyl group,
to react with formamidine in the presence of a base.
The third aspect of the invention relates to a process for producing 5-chloro-6-(1-fluoroalkyl)-4-pyrimidones represented by the following formula (1-B): 
wherein R1 and R2 have the same meanings as defined above, which comprises subjecting 6-(1-fluoroalkyl)-4-pyrimidone represented by the following formula (1-Axe2x80x2): 
wherein R1 and R2 have the same meanings as defined above, to chlorination reaction with a chlorinating agent.
In the following, the present invention will be explained in more detail.
R1 to R4 in the above-mentioned formula (1) are as mentioned below.
R1 to R4 in 6-(1-fluoroalkyl)-4-pyrimidone (Compound (1)) which is represented by the above-mentioned formula (1) which is a compound of the present invention and in 4-fluoro-3-oxocarboxylate (Compound (2)) represented by formula (2) which is a starting material, are as mentioned below.
R1 is a straight or branched alkyl group.
The alkyl group in R1 has 1 to 10 carbon atoms, preferably 1 to 4.
R2 is a hydrogen atom, or a straight or branched alkyl group.
R3 is a hydrogen atom, a straight or branched alkyl group or a chlorine atom.
R3xe2x80x2 is a hydrogen atom or a straight or branched alkyl group.
The alkyl group in R2, R3 and R3xe2x80x2 has 1 to 10 carbon atoms, preferably 1 to 4, and more preferably a methyl group.
R4 is a straight or branched alkyl group.
The alkyl group in R4 has 1 to 10 carbon atoms, preferably 1 to 4.
The compound (1) of the present invention is exemplified below.
6-(1-Fluoroethyl)-4-pyrimidone,
6-(1-Fluoro-1-methylethyl)-4-pyrimidone,
6-(1-Fluoropropyl)-4-pyrimidone,
6-(1-Fluoro-1-methylpropyl)-4-pyrimidone,
6-(1-Fluorobutyl)-4-pyrimidone,
6-(1-Fluoro-1-methylbutyl)-4-pyrimidone,
6-(1-Fluoropentyl)-4-pyrimidone,
6-(1-Fluoro-1-methylpentyl)-4-pyrimidone,
6-(1-Fluoroethyl)-5-methyl-4-pyrimidone,
6-(1-Fluoro-1-methylethyl)-5-methyl-4-pyrimidone,
6-(1-Fluoropropyl)-5-methyl-4-pyrimidone,
6-(1-Fluoro-1-methylpropyl)-5-methyl-4-pyrimidone,
6-(1-Fluorobutyl)-5-methyl-4-pyrimidone,
6-(1-Fluoro-1-methylbutyl)-5-methyl-4-pyrimidone,
6-(1-Fluoropentyl)-5-methyl-4-pyrimidone,
6-(1-Fluoro-1-methylpentyl)-5-methyl-4-pyrimidone,
5-Chloro-6-(1-fluoroethyl)-4-pyrimidone,
5-Chloro-6-(1-fluoro-1-methylethyl)-4-pyrimidone,
5-Chloro-6-(1-fluoropropyl)-4-pyrimidone,
5-Chloro-6-(1-fluoro-1-methylpropyl)-4-pyrimidone,
5-Chloro-6-(1-fluorobutyl)-4-pyrimidone,
5-Chloro-6-(1-fluoro-1-methylbutyl)-4-pyrimidone,
5-Chloro-6-(1-fluoropentyl)-4-pyrimidone,
5-Chloro-6-(1-fluoro-1-methylpentyl)-4-pyrimidone,
and the like.
The compound (2) which is a starting material to be used in the present invention can be easily obtained from a carboxylate 
Formamidine to be used in the present invention may be used in the form of a salt, for example, an acetate, a hydrochloride, a sulfate, etc., of formamidine.
An amount of the formamidine salt to be used is preferably 1-fold mole or more, more preferably 1- to 3-fold mole based on the amount of the compound (2).
The base to be used is preferably an alkali metal alkoxide such as sodium methoxide, sodium ethoxide, sodium butoxide, potassium t-butoxide, etc.
An amount of the base to be used is preferably 1-fold mole or more, more preferably 1- to 3-fold mole based on the amount of the formamidine salt.
Synthesis of the compound (1-A) may be carried out without using any solvent, and when a solvent is used, it is not particularly limited so long as it does not participate in the present reaction. There may be mentioned, for example, an alcohol such as methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, etc., an amide such as N,N-dimethylformamide, N,N-dimethylacetamide, etc., an ether such as tetrahydrofuran, dimethoxyethane, etc. Also, these solvents may be used singly or in admixture.
An amount of the solvent to be used is preferably 1- to 50-fold volume, more preferably 2- to 30-fold volume based on the amount of the compound (2).
In the synthesis of the compound (1-A), a reaction temperature to be employed is preferably xe2x88x9210 to 100xc2x0 C., more preferably 0 to 70xc2x0 C.
A reaction time in the synthesis of the compound (1-A) may vary depending on the concentration, temperature and amounts to be used, but generally is 0.5 to 15 hours.
The chlorinating agent to be used in the present invention is preferably a chlorine and sulfuryl chloride.
An amount of the chlorinating agent to be used in the present invention is preferably 0.9-fold mole or more, more preferably 0.9 to 4.0-fold mole based on the amount of the compound (1-Axe2x80x2).
In the synthesis of the compound (1-B), a solvent may be used or may not be used, and when a solvent is used, it is not particularly limited so long as it does not participate in the present reaction. For example, an aliphatic halogenated hydrocarbon such as dichloromethane, chloroform, dichloroethane, etc., an aromatic halogenated hydrocarbon such as chlorobenzene, etc., an amide such as N,N-dimethylformamide, N,N-dimethylacetamide, etc., an ether such as diethyl ether, tetrahydrofuran, dimethoxyethane, etc. may be used singly or in admixture.
An amount of the solvent to be used is preferably 0- to 50-fold volume, more preferably 2- to 30-fold volume based on the amount of the compound (1-Axe2x80x2).
In the synthesis of the compound (1-B) of the present invention, a reaction temperature to be employed is preferably xe2x88x9210 to 100xc2x0 C., more preferably xe2x88x925 to 70xc2x0 C.
A reaction time in the synthesis of the compound (1-B) of the present invention may vary depending on the concentration, temperature and amounts to be used, but is generally 0.5 to 10 hours.
The compound (1) of the present invention prepared as mentioned above may be subjected to post-treatments such as washing, extraction, concentration, etc., after completion of the reaction, and may be purified by conventionally known means such as recrystallization, various kinds of chromatography, etc., depending on necessity.
An aminopyrimidine derivative useful as insecticide, acaricide, fungicide, or nematocide can be obtained from the thus obtained compound (1).
For example, as shown below, by chlorinating the 4-position of 5-chloro-6-(1-fluoroethyl)-4-pyrimidone (compound (1-B)) which is one embodiment of the compound (1), 4,5-dichloro-6-(1-fluoroethyl)pyrimidine can be obtained which is an important synthetic intermediate of useful aminopyrimidine derivatives. 